1. Field of the Invention
This invention relates generally to projection screens and more particularly to a double concave screen system and method of assembly.
2. Description of Related Art
Images projected onto compound curved reflective surfaces are optically pleasing and more akin to reality. The illusion of size of image is increased, the depth of perception is enhanced and edge distortion is reduced. Projecting images onto curved surfaces is not new, but because of complex problems, such display screens have been limited to cylindrical shapes. It also has been difficult to produce a compound curved display surface that is reflectively dynamic and affordable. Recent technology has advanced the composition of the screen surface, greatly reducing the light bounce problem inherent to curved screens. Advances in the molding process and molding materials have also advanced to a point where compound curved screens are practical and affordable. It is desirable to provide a relatively large compound curved display screen for mass audiences that can be easily and inexpensively fabricated. It is further desirable for the large compound curved screen to occupy a minimum amount of space and to be installed with the least amount of interference with existing structures. There is a further need to provide a compound curved screen for the smaller audience such as the school or home that can be inexpensively molded, occupy a minimum amount of space, be lightweight and easily portable.
Yamashita, U.S. Pat. No. 3,964,822 describes a projection screen including a substrate having a metallic aluminum surface and a transparent film overlay. The metallic aluminum surface is provided with a pattern of directional irregularities and a pattern of craters. The projection screen is produced by subjecting an aluminum surface to a mechanical surface treatment to form a dense pattern of fine irregularities, etching the treated surface to form a crater pattern thereon and coating the resulting surface with a protective transparent film.
Holzel, U.S. Pat. No. 3,998,522 describes a screen such as those generally used for exhibiting projected images. A boxlike frame has a rim formed about its front. A membrane (the projection screen) covers the front with its margin extending to the vicinity of the rim. A cover encloses the back of the frame and is connected in sealed engagement to the margin of the membrane so as to form a plenum. Gas is withdrawn from the plenum whereby the membrane forms a concave image receiving surface curved in a relatively constant degree about a single point so that the image receiving surface takes on a spherical shape.
Rain, U.S. Pat. No. 4,022,522 describes a tailored membrane supported solely by a peripheral frame forms the front panel of a chamber. A source of vacuum or an air blower maintains a pressure in the chamber which differs from that of the ambient atmosphere. As a result, the tailored membrane is either drawn forward or pushed taut to provide a concave or convex viewing surface having a configuration determined solely by its tailoring.
Schudel, U.S. Pat. No. 4,089,587 describes an improved projection screen. The screen includes a film which is constructed of at least partially deformable, resilient material. One surface of the film has in combination a random matte texture and a substantially unidirectional striated texture. A layer of reflective material is deposited on the above-mentioned surface of the film to provide a high gain, damage resistant reflective surface. In one embodiment of the present invention, the layer of reflective material is located on the back surface of the film, and the front surface has a matte texture so that light from a projector or other source passes through the matte surface of the film to be reflected by the layer of reflective material on the back surface thereof. In another embodiment of the present invention, the layer of reflective material is located on the front surface of the film so that light projected on the screen is reflected by the layer of reflective material without passing through the film.
Nash et al., U.S. Pat. No. 4,750,808 describes a projection screen including a rectangular film having a back surface, a front surface and a periphery, a support frame and chamber connected to the periphery of the film for defining the shape of the periphery of the film, a device for creating a pressure differential between the front surface and the back surface of the film, a sensor for sensing the position of the film and indirectly sense the pressure differential on the film and a controller for controlling the device for creating the pressure differential in response to the sensor such that the position of the film is a predetermined position as a result of some pressure differential whereby the shape of the film is set by the shape of the frame which is connected to the periphery of the film and by the predetermined position of the film resulting from the pressure differential.
Zobel, Jr. et al., U.S. Pat. No. 5,128,130 describes a projection screen formed from a plurality of translucent fabric panels joined along overlapping peripheral edge portions to produce a reflective, curved front screen surface. Overlapping peripheral edge portions extend outwardly from the back surface of the screen and are configured to be substantially less reflective than the front or projection surface of the screen. Accordingly, the visibility of seams between adjacent fabric panels to a viewer viewing images projected onto the screen is diminished.
The prior art teaches the use of curved projection screens but does not teach a double concave screen mounted onto a lightweight and rigid blank and a method of assembly using vacuum suction. The present invention fulfills these needs and provides further related advantages as described in the following summary.
The present invention teaches certain benefits in construction and use which give rise to the objectives described below.
The present invention addresses the above described needs by providing a compound curved display screen of sufficient dimensions for commercial theaters, conventions, trade shows, etc. The present invention further addresses these needs by providing a compound curved display screen of sufficient dimensions for home theaters, instruction classes, sports lounges, etc. The invention comprises a molded unit having a surface of a toroid. The molded unit is comprised of a material such as polyurethane for both strength and lightweight. Placed on and bonded to the concave surface of the molded component is a reflective screen material with an anti-light bounce feature. The screen is mounted to the peripheral edges of the blank and then stretched and bonded to the toroidal surface of the blank using vacuum suction.
A primary objective of the present invention is to provide an apparatus and method of use of such apparatus that provides advantages not taught by the prior art.
Another objective is to provide such an invention method capable of mounting a flexible screen material to a double concave surface.
A further objective is to provide such an invention capable of preventing light bounce on the surface of the screen.
A still further objective is to provide such an invention comprising a fixture for holding a support blank with a screen stretched across it, and for providing vacuum suction between the support blank and the screen to enable stretch mounting the screen onto the blank.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.